Disposable tonometer cover with fluorescein dye

ABSTRACT

A cover and packaging and method for use in preventing infection in applanation tonometry eye testing. The cover has a circular transparent portion, a frustum shaped mounting portion and a frustum shaped handling flange. It is sterile, disposable, unitarily dispensable, and fits onto existing standard applanation tips. The circular transparent portion of the cover has an effective amount of a photoactive agent therein for enhancing the view of the calibration image during the pressure measurement.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation-in-part of U.S. Pat. application filed Apr. 10,1989, Ser. No. 07/335,237, entitled DISPOSABLE OCULAR DIAGNOSIS DEVICEAND METHOD.

FIELD OF THE INVENTION

The present invention relates to the prevention of the spread ofinfection during ophthalmic testing and more particularly to adisposable sterile cover for equipment used in measuring pressureswithin the eye.

BACKGROUND OF THE INVENTION

The pressure within the eye has long been regarded as a significant cluein assessing the health of the eye. Physicians in Egypt and Greece, ourearliest recorded civilizations, have regarded the hardness or pressureof the eye as being indicative of vision threatening eye disease.Initially, pressure was assessed with digital applanation. By thistechnique, the eye was balloted gently between opposing fingers of theleft and right hand, and judgment was made by the clinician as to normalor abnormal pressure. Digital tonometry continued in practice throughoutthe early evolution of ophthalmology. Modern ophthalmic surgeons arefamiliar with the application of digital tonometry and can quite readilytell the difference between normal or abnormal pressures of moderatemagnitudes.

The present uses of tonometry respect and honor age old traditions ofdigital tonometry. It is first and foremost important to know whetherthe pressure is normal or whether the pressure is significantly out ofrange from normal. This relates to both high and low pressures. However,the accumulation of accurately measured serial data over a patient'socular history allows trending of pressures and frequently accurateprediction of certain pressure related events which may be visionthreatening. Intraocular pressure is important in the differentialdiagnosis of acute eye problems. It is often important to measure theintraocular pressure in an eye which otherwise may have acuteinflammatory, viral, bacterial, ischemic, or traumatic etiologies.Intraocular pressures also need to be measured in the immediatepost-operative period when intraocular contamination is at greatestrisk. A sterile instrument is thus desirable. Careful slit lampbiomicroscopic observation during the acquisition of applanationtonometry also allows a direct view of the intraocular pulse through themires of the applanation device. This observation has significance inaccessing carotid and intracranial blood flow and ocular perfusion.

The evolution of the ophthalmic subspecialty as a scientific as well asan artful practice, however, required standardization and quantificationof these measurements. Consequently, one of the first biometricparameters to be utilized was tonometry. Schiotz tonometry is amechanical, non optical gravity dependent device which measuresintraocular pressures by using a metallic weighted probe to indent thecornea with the patient in a supine position. Although very smallvariations in weight are significant, accuracy has been found to bereproducible. Intraocular pressure curves and distributions ofintraocular pressure within normal populations have been formulated.Normal and abnormal ranges and standards have been identified. Thisimportant biometric data accumulation has founded the basis forinvestigation into the etiology and treatment of glaucoma, a diseasewhereby the intraocular pressure damages the optic nerve.

The means for increased convenience of obtaining this measurementfollowed the introduction of the slit lamp biomicroscope, and additionalforms of pressure measurement were developed. In particular, what isknown in the profession as the Goldmann applanation tonometer wasdesigned for use at the stereo, slit lamp biomicroscope for pressuremeasurement convenient and comfortable to both patient and physician.The Goldmann device currently is the most widely used instrument fordetermining intraocular pressures and is supplied by Haag Sterit Ag.Ophthalmological Instruments, 3097 Liedefeld, Berne, Switzerland. TheGoldmann device uses an applanation tip which is supported on an armattached to a slit lamp biomicroscope. It is placed in contact with thesurface of the cornea with the patient in the seated position. By use ofa slit lamp, the technician views the tip-cornea contact area whilevarying the applied force on the tip to flatten the cornea. When theflattened corneal area coincides with a standard calibration image ofthe tip, the force measured is recorded. Viewing of the calibrationimage is enhanced by applying a fluorescein dye to the cornea.

Even though forces of small magnitude are involved, the accuracy ofapplanation tonometry is excellent. It is recognized as theinternational standard to which all other measurements are compared.Applanation tonometry by the Goldmann technique is the standard initialscreening for intraocular pressure related problems.

This very beneficial tonometry process also carries with it certainrecognized disadvantages. It is recognized that bacterial and viralinfections have been spread through patient contact with infectedtonometers. It is known, for example, that viral and bacterialinfections can be spread fomitically. The applanation tip is a carrierof these contaminants. Adenovirus of several strains is readilytransmissible by tear or mucus membrane contact. Hepatitis is likewiseknown to be present in the aqueous secretion of tears and it is likelythat inoculation to a second patient is not only possible but probable.The active AIDS virus has been identified in tears as well as in otherglandular secretions.

To avoid infection, attempts have been made to sterilize the applanationtip between uses. Sterilization methods have not been entirelysuccessful, in that they are not reliable, especially with viralinfections. Second, disinfectant can itself cause problems. Commerciallyavailable hydrogen peroxide of the type used with contact lenses hasbeen used; however, there are reported cases of corneal toxicity causedby use of hydrogen peroxide to sterilize an applanation tip. Residues ofcommon disinfectants such as household bleach, isopropyl alcohol oracetone can immediately desiccate and/or injure the corneal epithelium.In addition, repeated sterilization of the sensitive applanation tipwill damage the tip.

In applications of community screenings and portable tonometry clinics,it is impractical, if not impossible, to perform these time consumingdisinfectant processes. Thus, there is an urgent need for a practicalmeans to prevent the spread of infection in tonometry testing.

SUMMARY OF THE INVENTION

According to the present invention, a disposable cover for anapplanation tip is provided. The cover is unitarily formed fromtransparent material suitable for direct contact with a patient's eye.The material is flexible and conforms closely to the applanation tip sothat it will stretch over the tip and will be held in place by theresiliency of the material during the eye testing procedure. Thematerial is transparent and forms a circular eye contact portioncovering the optically transparent area of the applanation tip. Thisseparates the tip from the eye and prevents contamination of the tipthrough contact with the eyelids or lashes. Surprisingly, the cover isdesigned so that the optical characteristics of the tip are notmaterially affected. A flange is formed on the cover for use inmanipulating removal from the tip. The cover is designed to be installedwithout having to be grasped or contacted by hand, thus eliminating handcontamination of the cover.

An effective amount of a photoactive agent, such as fluorescein dye, maybe introduced directly into the uncured transparent material used toform the unitary body of the disposable tonometer cover. Preferably thephotoactive agent is added to the circular transparent portion of thetonometer cover so that the agent does not block too much of the lightrequired for an accurate applanation measurement with the disposablecover. The method of making a disposable cover with a photoactive agentinvolves mixing the photoactive agent into the silicone prior to curingthe silicone in a tonometer mold.

BRIEF DESCRIPTION

The present invention will be more easily understood from the followingdetailed description of the preferred embodiment when taken inconjunction with the attached drawings in which:

FIG. 1 is an elevation view of eye testing equipment using a disposableocular diagnosis device of the present invention;

FIG. 2 is an enlarged partial sectional view showing a patient's eye inthe initial contact position with the ocular diagnosis device of thepresent invention;

FIG. 3 is a view similar to FIG. 2 showing flattening of the cornea bythe ocular diagnosis device;

FIG. 4 is an enlarged sectional view of the ocular diagnosis device ofthe present invention; and

FIG. 5 is an enlarged section view illustrating the method ofinstallation of the disposable diagnosis device on an applanation tip.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings wherein like reference characters designatelike or corresponding parts throughout the several views, there isillustrated in FIG. 1 a slit lamp type eye examination device which forpurposes of description is generally identified by reference charterer10. The slit lamp 10 is illustrated in FIG. 1 used in conjunction withthe disposable ocular diagnosis device or cover 12 of the presentinvention. For purposes of illustration, cover 12 is shown with the slitlamp Model 900BM distributed by Haag-Streit A.G., 3097 Liedefeld,Switzerland. Slit lamp 10 is used with an applanation tonometer 14 ofthe Goldmann type which is also available from Haag-Streit A.G. as Model#900. It should be understood of course that the Haag-Sterit equipmentis described in the present application for purposes of illustration ofthe environment in which the disposable sterile cover of the presentinvention is used and that the present invention has applications withother types of applanation equipment. In the applanation equipmentillustrated in FIG. 1, the patient 16 is shown with the forehead andchin resting on the equipment to prevent head movement. A light source18 projects a beam of light into a prism (not shown). The prism reflectsthe light onto the eye of the patient. The doctor or technicianconducting the test examines and views the prism through a microscopictype lens system 20.

Applanation tonometer 14 is supported by arm 22. Tonometer 14 ispositioned in the light path and in contact with the surface of thecornea. Applanation tonometer 14 has a base 24 and a calibrated dial 26thereon. An arm 28 extends upward from the base and removably supportsthe applanation tip 30 from a mounting bracket 32.

Applanation tip has a circular cross section with a reduced diameterlens portion 36 on one end and a cylindrical mounting portion 38 at theother end (See FIG. 2). Mounting bracket 32 has a bore extendingtherethrough into which the mounting portion 38 is removably mounted.Thus, the light path "L" extends through the bracket 32 and applanationtip 30 and onto the eye "E" of the patient. As can be seen according tothe present invention, cover 12 mounts on the applanation tip 30 toprevent contact between the eye and tip 30.

In eye testing, the position of the applanation tonometer on thepatient's eye is adjusted until it is positioned as shown in FIG. 2.During this positioning procedure some relative movement between thetonometer and the cornea occurs. The cover 12 must be held on the tip toprevent dislodgement or movement during this initial positioningprocess. The tonometer tip in the Goldmann type device has a calibrationimage formed in the optics thereof. This image can be viewed by thedoctor or technician along with light path "L". The tonometer tip 30 isthen moved in the direction toward the eye to deform and flatten thecorneal surface (see FIG. 3) until the contact between the tonometer tipand the outer surface of the eye completely fills the surfaceapplanation area. The force applied to the tonometer tip 30 in thedirection of arrow F (see FIG. 2) is measured, and through priorcalibration, the internal eye pressure can be determined. In theGoldmann type tonometer, dial 26 is calibrated and by turning the dialforce can be progressively applied through the arm 28 to the tonometertip in the direction of arrow F. The forces applied to the tonometer tipto deform the eye surface are of a very small magnitude and thus, theequipment is fragile and must be handled with care.

To use the present invention, the tip 30 is removed from the mountingbracket 32. The cover 12 is installed on the tip 30 as will be describedherein in greater detail. The tip 30 with cover 12 thereon is placed inthe mounting bracket 32 before the patient's head is positioned in theequipment. Due to the fact that the cover 12 is made from transparentmaterial, the applanation testing can be performed without the tip 30itself coming into contact with the patient's eye. As can be seen inFIG. 2, the cover 12 not only covers the lens portion 36 of theapplanation tip but it also extends back along the tip a sufficientdistance to eliminate the possibility of the patient's eyelids or lashescontacting the tip during the positioning or testing procedure. Oncetesting of a patient is complete, the cover can be removed and disposedof.

The details of the structure of cover 12 are shown in FIG. 4. Accordingto the present invention, the cover is constructed from an opticallyneutral transparent plastic material such as optical silicone compoundedby Airmec Incorporated, 2102 Vanco Drive, Irving, Tex. 75061, SiliconeCompound #10R45-1. It is anticipated that other acceptable compoundscould be used. In the illustrated embodiment, the cover has a frustumshaped mounting portion 40 tapering at an angle X which preferably is7.75 degrees. The taper of portion 40 is selected to be slightly greaterthan the taper of tip 30. Portion 40 is preferably designed to have adiameter at the larger end to cause a slight interference fit with thecorresponding portion of tip 30. Portion 40 has a circular transparentportion 42 integrally formed on its smaller end. Transparent portion 42is preferably sized to correspond to the smaller end of tip 30. Ahandling flange 44 is integrally formed to the larger or base end of themounting portion 40. In the preferred embodiment, flange 44 is in theform of a frustum tapering at angle Y which is preferably 30 degrees.The magnitude of angle Y is selected to cause the flange 44 to extendaway from tip 30 to provide access to flange 44 during removal andinstallation. Flange 44 has a plurality of annular stiffening ridges 46formed therein to assist its rigidity. It is to be understood thatflange 44 could be made in other shapes and its stiffness could beenhanced in other ways.

Preferably, the circular transparent portion 42 has a thinner wall thaneither the mounting portion 40 or handling flange 44. The circulartransparent portion 42 is preferably about 0.005 inches thick; however,it is believed to perform within a range of 0.002 to 0.012 inches thick.The wall of frustum shaped portion 40 is shown varying in cross section.The portion 40 tapers from its thinnest wall adjacent the portion 42 toits thickest wall adjacent handling ring 44. In the preferredembodiment, portion 40 has a thickness of from 0.010 to 0.020 inches.

The fluorescein dye is introduced into the uncured silicone used to formthe unitary body of the disposable tonometer cover 12. The tonometercover 12 with the dye formed in the silicone may be made by mixing a tenpercent aqueous solution of fluorescein sodium dye into the siliconeprior to curing the silicon in the mold. If, however, the siliconebecomes saturated with the fluorescein dye solution at a concentrationof the dye in the silicone that is too low for accurate eye applanationmeasurements, an effective amount of a substantially pure powdered solidfluorescein dye may be mixed into the silicone prior to curing.

When the tonometer cover 12 is formed with dye throughout the siliconebody of the cover 12, it may in some instances block too much of thelight required for an accurate applanation measurement with thetonometer cover 12. Therefore, in the most preferred embodiment of theinvention, an effective amount of the powdered fluorescein dye isintroduced into the circular transparent portion 42 of the disposabletonometer cover 12 so that the mounting portion 40 remains substantiallyfree of the dye.

An effective amount of the fluorescein dye may be introduced into thecircular transparent portion 42 of the tonometer cover 12 during themanufacturing process. The method of manufacture involves the use ofmold forms for the tonometer cover 12 and injection molding equipment.First, blocks are inserted into the tonometer mold and the mold isclosed to create a molding volume conforming to the circular transparentportion 42 of the tonometer cover 12. Second, a mixture of silicone witha dispersion of an effective amount of powdered fluorescein dye isinjected through one or more sprew gates into the circular transparentportion of the tonometer mold. Third, the mold is opened, the blocks areremoved from the mold, and the mold is closed again. Fourth, silicone isinjected through one or more sprew gates into the previously blockedportion 42 of the mold that conforms to the rest of the tonometer cover12. The newly injected silicone will contact and bond upon curing to thepreviously injected silicon with fluorescein dye.

The silicone is injected into the mold at pressures as high as threethousand pounds per square inch so that every part of the mold iscompletely filled with silicone. The temperature of the mold ismaintained between about 280 degrees to about 320 degrees Fahrenheit forcuring the silicone. Therefore, the third and fourth steps of the abovedescribed process should preferably be performed quickly, before thesilicone in the circular transparent portion 42 of the mold becomescompletely cured, otherwise the two portions of silicone may notproperly bond together to form the unitary body of the tonometer cover12.

The curing of the silicone is completed in the mold to produce aunitarily formed tonometer cover 12 having an effective amount of thefluorescein dye in the circular transparent portion 42. Once thetonometer cover 12 is properly cured, it is removed from the mold andpackaged for distribution. The method of manufacturing the tonometercover 12 may be further improved if a suitable release agent isinitially applied to the mold surfaces so that after curing thetonometer cover 12 may be more easily removed from the mold.

In FIG. 5, the cover 12 is shown in its cooperating sterile packagingassembly 50. According to a feature of the present invention, thepackaging assembly 50 cooperates with the cover 12 to assist in themounting of cover 12 on tip 30. Packaging assembly consists of a semiridged base 52 and a sealing cap 54. Base 52 can be formed from suitablematerial such as high impact styrene or the like. Base 52 is formed froma flat sheet to have a plurality of receptacles 56 formed therein, eachof a size and shape to receive the tip 12 therein. Receptacle 56 has aflat circular bottom portion 58, whose inside surface corresponds to theoutside surface of the transparent portion 42. Receptacle 56 also has afrustum shaped portion 60 which corresponds in shape to the exteriorsurface of mounting portion 40. In addition, receptacle 56 correspondsin shape to a portion of the exterior of cap 12 and preferably has afrustum shaped portion 62 exactly corresponding in shape to the exteriorof mounting portion 44.

To use the packaging 50, cap 54 is pealed back as shown in FIG. 5 toopen one receptacle 56. The cover 12 had been previously sterilized andsealed in the receptacle 56. (Sterile pharmaceuticals used for tonometrymay be packaged within, or photo active agents such as fluorescein dyemay be added into the tip.) Tip 30 is inserted into the cover 12 byforcing down in the direction of arrow "F" while the bottom portion 58rests on a work surface. As shown in FIG. 5, air 66 will be trappedinside the cover 12 by the tip 30. If the air is not completely removed,the optical path will be distorted and the eye testing could not beaccurately performed. To remove the air 66, tip 30 is forced in thedirection of arrow F compressing portion 42 between tip 30 and surface58. This will remove the entrapped air. Tip 30 will have an interferencewith portion 40 to mount the cover 12 on tip 30. In this manner, thecover 12 can be installed on tip 30 without being handled. Removal ofthe cover can be accomplished by grasping the handling flange 44 withforceps or by hand. The cover will turn partially inside out.

The foregoing description of the present invention relates only to thepreferred embodiment. It is to be understood that alterations andmodifications can be made in the cover without departing from the spiritand scope of the invention as defined by the appending claims.

What is claimed is:
 1. A disposable cover for use with a tip ofapplanation tonometry equipment for contacting an eye, said covercomprising: a body of flexible, optically transparent material forremovably mounting on the tip, said body having a mounting portioncomprising means for recovering said tip and a circular transparentportion, attached to said mounting portions said circular transparentportion having an effective amount of a photoactive material therein forenhancing the view of an image therethrough.
 2. A disposable coveraccording to claim 1, wherein said photoactive material comprisesfluorescein dye.
 3. A disposable cover for use with the contacting tipof applanation tonometry equipment comprising a unitarily formed body offlexible optically transparent material for removably mounting on theapplanation tip, said body having a frustum shaped mounting portion witha handling flange extending from a base end of the mounting portion anda circular transparent portion extending from and closing the end ofsaid mounting portion, said circular transparent portion having aneffective amount of a photoactive agent therein for enhancing the viewof the calibration image.
 4. The cover of claim 3 wherein said handlingflange is frustum shaped.
 5. The cover of claim 3 wherein said circulartransparent portion is in the range of 0.001 to 0.012 inches thick. 6.The cover of claim 3 wherein optically transparent material comprisessilicone.
 7. The cover of claim 3 wherein said photoactive agentcomprises fluorescein dye.
 8. A disposable cover for removably mountingon an eye contacting applanation tip assembly for use in eye diagnosisto cover the tip and to prevent contact between the patient's eye andthe tip thereby preventing transmission of infection between patients bythe tip during use, the tip having a generally tapered shape with alarger end and a smaller eye contacting end, a circular optical lenssurface formed on the smaller eye contacting end of the tip for viewingthe patient's eye and for deforming the cornea surface of the patient'seye to measure the distortion of the eye and pressure within the eye, anoptical path through the body of the tip and through the circularoptical lens surface, said disposable cover comprising:a unitarilyformed body of flexible material; a circular transparent portion on saidbody for contacting and for covering the circular optical lens surfaceof the tip, said circular transparent portion sized to correspond to thesmaller eye contacting end of the tip, said circular transparent portionhaving an effective amount of a photoactive agent therein for enhancingthe view of a calibration image for the pressure measurement; and amounting portion means on said body for removably mounting said body inan interference fit on the tip and for retaining said circulartransparent portion adjacent the circular optical lens surface of thetip, thereby improving the optical and contact interface between saidcircular transparent portion of said disposable cover and the circularoptical lens surface of the tip so that distortions in the measurementof pressure within the patient's eye are minimized during use of thetip, said mounting portion means having a generally tapered shape with alarger end and a smaller end, the smaller end of said mounting meansintegrally formed with said circular transparent portion.
 9. Thedisposable cover of claim 8 wherein the maximum thickness of saidmounting portion means is greater than the thickness of said circulartransparent portion of said disposable cover.
 10. The disposable coverof claim 8 wherein the thickness of said circular transparent portion isbetween 0.002 inches and 0.012 inches and the thickness of the largerend of said mounting portion means is between 0.010 inches and 0.020inches.
 11. The disposable cover of claim 8 further comprising ahandling flange means integrally formed on said body for handling thedisposable cover, installing the disposable cover on the tip, andremoving the disposable cover from the tip.
 12. The disposable cover ofclaim 11 wherein said handling flange means diverges from the tip sothat said handling flange means can be grasped without touching the tipwhereby cross infection between patients is prevented.
 13. Thedisposable cover of claim 12 wherein said handling flange means iscontinuous around the larger end of said mounting portion means so thatsaid handling flange means can be grasped from any direction duringinstallation on the tip and removal from the tip.
 14. The disposablecover of claim 13 wherein said handling flange means is generallyfrustum shaped and tapers at an angle substantially greater than thetaper of the tip so that said handling flange means extends away fromthe tip to provide access to said flange during installation on the tipand removal from the tip.
 15. The disposable cover of claim 14 whereinsaid handling flange means has a plurality of annular stiffening ridgesformed therein to assist its rigidity and handling strength.
 16. Thedisposable cover of claim 11 wherein said handling flange means iscontinuous around the larger end of said mounting portion means so thatsaid handling flange means can be grasped from any direction.
 17. Thedisposable cover of claim 16 wherein said handling flange means isgenerally frustum shaped and tapers at an angle substantially greaterthan the taper of the tip so that said handling flange means extendsaway from the tip to provide access to said flange during installationon the tip and removal from the tip.
 18. The disposable cover of claim17 wherein said handling flange means has a plurality of annularstiffening ridges formed therein to assist its rigidity and handlingstrength.
 19. In combination, (a) a disposable cover for an eyecontacting applanation tip assembly for mounting on an eye contactingapplanation tip assembly for use in eye diagnosis to cover the tipassembly and to prevent contact between the patient's eye and the tipassembly thereby preventing transmission of infection between patientsby the tip assembly during use and (b) a sterile packaging assembly forsaid disposable cover and for assisting in mounting said disposablecover on the tip assembly, the tip assembly having a generally taperedshape with a larger end and a smaller eye contacting end, a circularoptical lens surface formed on the smaller eye contacting end of the tipassembly for viewing the patient's eye and for deforming the corneasurface of the patient's eye to measure the distortion of the eye andpressure within the eye, an optical path through the body of the tipassembly and through the circular optical lens surface, whereinsaiddisposable cover comprises: a unitarily formed body of flexiblematerial; a circular transparent portion on said body for contacting andfor covering the circular optical lens surface of the tip assembly, saidcircular transparent portion sized to correspond to the smaller eyecontacting end of the tip assembly, said circular transparent portionhaving an effective amount of a photoactive agent therein for enhancingthe view of a calibration image; and a mounting portion means on saidbody, said mounting portion means having a generally tapered shape witha larger end and a smaller end, the smaller end of said mounting meansintegrally formed with said circular transparent portion, said mountingportion means for removably mounting said body in an interference fit onthe tip assembly and for retaining said circular transparent portionadjacent the circular optical lens surface of the tip assembly, therebyimproving the optical and contact interface between said circulartransparent portion of said disposable cover and the circular opticallens surface of the tip assembly so that distortions in the measurementof pressure within the patient's eye are minimized during use of the tipassembly; and said sterile packaging assembly encloses said disposablecover, said sterile packaging assembly comprising: a base of a size andshape to conform to the exterior of said circular transparent portion ofsaid disposable cover and to conform to at least a portion of theexterior of said mounting portion means of said disposable cover; and aremovable cap closing said receptacle adjacent to the larger end of saiddisposable cover within said base of said receptacle whereby when theremovable cap is of removed, said base of said receptacle may be used byinserting the tip assembly into said disposable cover to removably mountsaid disposable cover on the tip assembly and to force ambient gasesfrom the interface between the tip assembly and said circulartransparent portion of said disposable cover without handling saidcircular transparent portion of said disposable cover and withouthandling said mounting portion of said disposable cover.
 20. Adisposable cover for use with a tip of applanation tonometry equipmentfor contacting an eye, said cover comprising: a unitary body offlexible, optically transparent material for removably mounting on thetip, said body having a hollow frustum shaped mounting portion with ahandling flange extending from a base end of the mounting portion and acircular transparent portion extending from and closing an opposite endof said mounting portion, said circular transparent portion having aneffective amount of a photoactive material therein for enhancing theview of an image therethrough.